A government advisory board, fearful of the potential for biomedical terrorism, asked the journals Science and Nature not to publish details of studies on a highly transmissible, deadly bird flu virus.

The experiments, in which scientists created the virus, A(H5N1), were initially conceived as a way to find out what genetic changes in the virus would make it more transmissible. It was thought the information would help in monitoring naturally occurring mutations and predicting when the virus could become a pandemic.

But now that the scientists have succeeded in making an easily transmissible form of the virus, the National Science Advisory Board for Biosecurity has requested that details of the studies not be released in order to prevent the information from falling into the wrong hands. For instance, terrorists could use the information to create deadly viruses that could be transmitted by coughing or sneezing, thereby setting off epidemics.

“I’m sure there will be some people who say these experiments never should have been done,” Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, told The New York Times.

Although the panel cannot force the journals to cut the details of these studies, the editor of Science, Bruce Alberts, said the journal was seriously considering withholding some information as long as the government established a system that would release the missing information to legitimate scientists who need it.

Bird flu rarely infects humans, but when it does, it is usually fatal. Since 1997, when it was first detected, half of the nearly 600 people who have had it have died. Most of the cases have been in Asia, and most of them caught it directly from birds. However, scientists have always worried that if bird flu became easily transmissible between humans, it could spark one of the deadliest pandemics ever.

The National Institutes of Health paid for both studies, which were conducted in ferrets, animals considered a good model for showing how flu viruses will behave in people.